PHP 阻止数据在循环中回显两次

Question

考虑下面的简单代码，它应该阻止相同的值被回显两次

$sql = "SELECT * FROM events 
        WHERE event_date BETWEEN $curDate AND $date AND sport_type ='Rugby' 
        ORDER BY event_date ";

$lasttournament=""
echo'<select name="tournament" />';
 while($played>$venue){
   $tournament = $row['tournament'];

        if($tournament !== $lasttournament){
          $lasttournament = $tournament;
          echo'<option value="'.$tournament.'">'.$tournament.'</option>';           
         }//if 
      }//while

但是，我的代码没有给出所需的结果，如下图所示。

我显然错过了一些东西，因为每个锦标赛应该只显示一次

Answer 1

如果您只需要tournament字段，请尝试使用distinct -

SELECT DISTINCT tournament FROM events 
    WHERE event_date BETWEEN $curDate AND $date AND sport_type ='Rugby'
    ORDER BY event_date

或者尝试使用分组依据 -

SELECT * FROM events 
    WHERE event_date BETWEEN $curDate AND $date AND sport_type ='Rugby'
    GROUP BY tournament 
    ORDER BY event_date